1. Field of the Invention
This invention relates to a treatment method of athlete's foot and particularly to a method for curing dermatophytosis or athlete's foot by application of heat thereto. More specifically, the present invention relates to a medical application of a laser beam for curing athlete's foot by killing ringworms by burning.
2. Description of the Prior Art
Various methods have been proposed to treat athlete's foot. The athlete's foot is dermatophytosis of the foot caused by ringworms living in the skin surface, and the currently most common treatment method is a chemical therapy, including application of a medical substance to the affected part and dosage of an antibiotic substance. The other methods include application of heat to the affected part by hot water or infrared lamp. However, none of these prior art methods is satisfactory and there has been a need to develop an improved method for curing athlete's foot.
Among the various treatment methods, attention here will be focused on the thermal treatment method in which heat is applied to the affected part of a foot. FIG. 1 is a table showing the measured results of lethality in % of ringworms with applied temperature and time taken as parameters. It is seen from the graph that the application of heat approximately at 90.degree. C. or more for one second can kill the ringworms completely. However, to heat the affected part of a patient's foot to such a high temperature by hot water or infrared lamp is practically impossible because other side effects, such as burn, will be brought about.
Therefore, in accordance with the prior art thermal treatment method, it has been common practice to heat the affected part to 50.degree. C. for about 10 seconds, which is considered to be a tolerable upper limit for a human being. Under the condition, the lethality of ringworms is 60% as shown in the table. If the time of heat application is reduced to 5 seconds, the lethality of ringworms drops to 30%. It is also seen from the table that the lethality of ringworms decreases as the temperature is decreased below 50.degree. C. Thus, the conventional thermal treatment method has not been effective because, in order for it to be effective, a higher temperature must be maintained for a longer time duration, which then causes the patient to undergo an uncomfortable process. On the other hand, if the treatment conditions are set to be comfortable for the patient, then the effectiveness in treatment decreases dramatically and the lethality of ringworms becomes 50% or less, which is unsatisfactory in many respects.
In the meantime, medical applications of various lasers, such as CO.sub.2 laser and YAG laser, in various fields of medical treatments and therapies are becoming increasingly popular. However, so far, no proposal has been made to use CO.sub.2 laser and YAG laser for the treatment of athlete's foot. For example, the CO.sub.2 laser has been mostly used as a laser surgical knife, and it has also been used to remove a trauma and a burn. In this case, however, the heat energy of a laser beam emitted from the CO.sub.2 laser is used to have that portion of the tissue which is irradiated by the laser beam evaporated to carry out cutting of tumor tissue or removal of trauma or burn. In this technique, the laser beam is used at such an extremely high temperature as to cause evaporation of a laser-irradiated portion of the tissue, and, thus, this technique cannot be directly applied to the treatment of athlete's foot.